Stereoscopic images provide three-dimensional (3D) representations of objects and scenes using multiple two-dimensional (2D) images. Stereoscopy has been commonly used in motion pictures, holography, photography, and other fields for many years. As the quality of stereoscopic imagery has improved, it has become increasingly adopted in many environments. Stereoscopic imagery is now used, for example, during aerial refueling to aid in directing the refueling boom toward the fuel receptacle of the refueling aircraft. Numerous other applications of stereoscopic imagery are found in a wide array of entertainment, commercial, military, medical, aerospace, and other settings.
Typically, stereoscopic images make use of ‘binocular vision,’ which incorporates at least two separate images taken at different viewing angles corresponding to the different angles of vision produced by a viewer's two eyes. Upon viewing, the two images are isolated from each other (using various physical, optical and/or other techniques) such that each of the viewer's two eyes receives only one of the two images, creating separate left-eye and right-eye retinal images. When viewed in this manner, the human brain uses the differences between the separate left-eye and right-eye images as cues to the three-dimensional position of objects in the scene, thereby producing the visual percept of objects seen in various 3D positions in front of the observer's eyes.
One problem commonly associated with stereoscopic images, however, involves difficulty in framing the various objects within in the confines of the two-dimensional representation. So-called “frame violations” typically result when objects appearing in front of the viewing surface (“the frame”) are clipped off by the edge of the display frame, thereby giving the illusion that closer objects are blocked by a surface that appears to be behind the closer object; this is contrary to the normal experience of interposition, where closer objects block the view of farther objects. In the case of mid-air refueling, for example, the refueling boom may appear in front of the stereo window (formed by the edge of the display, typically a panel-mounted flat panel display), thereby creating the potential for an unnatural appearance when a portion of the boom appears to be obscured by the display edge “behind” the boom. The visual paradox created by this occlusion of the stereoscopic frame potentially contradicts the binocular disparity of the stereoscopic image in the viewer's mind, thereby disturbing the viewer's accurate perception of three-dimensional position in space.
Accordingly, it is desirable to create a stereoscopic display that reduces or eliminates stereoscopic frame violations. In addition, it is desirable to create a stereoscopic viewing system suitable for use in aerial refueling that reduces or eliminates stereoscopic frame violations. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.